Method and apparatus for removing lead containing ingredients from hydrocarbon fuels



S- 'RASMUSSEN INGREDIENTS FROM HYDROCARBON FUELS Filed May 29, 1944INVENTOR. I WV ymm ATTORNEYS METHOD AND APPARATUS FOR REMOVING LEADCONTAINING ELIIII-II Aug. 31

Patented Aug. 31, 1948 anazzs METHOD AND APPARATUS FOR REMOVIN LEADCONTAINING INGREDIENTS FROM HYDROCARBON FUELS Sophus Rasmussen, AlbertLea, Minn., 'assignor to American Gas Machine Company, Albert Lea,Minn., a corporation of Minnesota Application May 29, 1944, Serial No.537,827

:UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to the generating and conditioning of hydrocarbonfuels containing tetra-ethyl lead, such as leaded gasoline, to enablesuch fuels to be burned successfully in pressure type systems forheating, cooking and illumination.

Heretofore, to applicants knowledge, it has been impractical andcommercially impossible to successfully utilizegasoline containingtetraethyl lead in gasoline burner systems of the pressure type. Suchsystems employ generators whereinthe fuel is introduced, vaporized andpassedon by pressure and they also contain small orifices, Valves andother restricted passages which, become easily clogged withaccumulations of any deposits or sludge. In the vaporization of theleaded gasoline in the generator tube or other retort, the temperaturesare such that a cracking or decomposition of the tetra-ethyl lead occursresulting in production of atoms .or extremely minute particlesof theelement lead as well as some small amount of lead. oxide due to somepresence of airin the generator. These atoms and particles, I havediscovered, will deposit upon surfaces in small and restricted passagesof the system or apparatus, clogging parts of the device ahead of theactual burner jets. The actual burning of the vaporized leaded fuel, ofcourse, produces particles of lead oxide in the burner structure itselfwhere air is admixed with the vaporized fuel, further clogging passagesand ports and making such systems inoperative after leaded gasoline hasbeen utilized for a relatively very short period of time.

Furthermore, the production of-minute particles of lead oxide throughthe burning of gasoline vapor-containing tetra-ethyl lead orconstituents thereof is dangerous to human and animal life, suchparticles being toxic when breathed or swallowed. Various attempts havebeen made to solve the problems enumerated herein, both for the purposeof enabling pressureburner systems to 'be utilized to successfully burnleaded gasoline and for the further purpose of removing the grave dangerto human life.

It is an object of my invention to provide a comparatively simple, buthighly successful method whereby the toxic and solid or cloggingconstituents of tetra-ethyl lead and its oxides formed in vaporizing andburning of the fuel are substantially eliminated from the burner systemas the fuel is being vaporized in the generator and prior to entrance ofthe vapors into the burner proper and, of course, prior to actualburning.

' A further object is the provision of a simple and highly efficientapparatus for substantially eliminating the objectionable and dangerousconstituents of leaded gasoline to enable such fuel to be burnedsuccessfully and safely in pressure systems.

These and other objects and advantages-of my (01. nae-11' 2 inventionwill more fully appear from the following description made in connectionwith the accompanying drawings, wherein like reference characters referto the same parts throughout the views, and in which Figure 1 is alongitudinal, sectional view of a generator detached from a gasolineburner system constructed to carry out my improved method and embodyingthe principles of my improved apparatus;

Figure 2 is an end view of the same; Figure 3 is a cross section takenon theline 3-3 of Figure 1;

Figure 4 is a side elevational view illustrating a bat of matted metalfilaments, such as steel wool before the same is compressed orcondensed; and

Figure 5 is a longitudinal elevation of a somewhat different form of myapparatus. v

The tetra-ethyl lead contained in leaded gasoline or other analogoushydrocarbon fuels is held.

in suspension in the form of very minute globules and remains in suchform until it is heated to such temperature either by vaporization ,ofthe fuel at high temperature or in the subsequent burning, to crack orotherwise decompose the tetra-ethyl lead thereupon liberating free leadatoms or minute particles which in the presence of air readily formparticles of lead oxide.

After exhaustive testing of various chemicals,

filters and methods for eliminating the constituents of tetra-ethyl leadboth upon burning and prior to burning of the vaporized fuel, I havediscovered a method and apparatuswhich by actual long recurrent testshave demonstrated an efliciency for removing as high as of all leadconstituents of the prepared leaded gasoline.

My method is preferably carried out within the generator or vaporizingtube itself as the leaded,

hydrocarbon fuel is heated at relatively high temperatures for producinga combustible vapor and gas. It can be carried out, although not assuccessfully, at points in the pressure burner system immediately aftervaporization of the fuel and where the temperature of the mixture issuch that the tetra-ethyl lead is still in cracked or decomposed state.

In the form of the apparatus illustrated in the drawings Figs. 1 and 3,there is shown a relatively large generator tube II which hascircumferential rabbeted ends Ila wherein are secured as by- Weldingclosure discs [2 and I3 respectively, closure disc I2 at the fuelentrance of the generator tube being tapped to receive a straightfittingor plug I4 having an axial passage Ila in the inner end thereof whichcommunicates with a lateral port Pic of a nipple l5 which is connectablewith the tank or other source offuel supp At the discharge as shown, ashort tubular fitting l6 is screwend of the generator tube It,

ed therewith and communicating with the axial,

port in tube IS. The tube H is filled with the exception of its endswith adens'ely compressed or related mass of metal fragments orparticles preferably steel wool, the mass of steel wool as utilizedbeing greatly compressed to provide a dense homogenous filler having aminute porosity sufficient, however, to permit passage of vapors andgases. pressed in such manner that its density adjacent the dischargeend of the vaporizing tube is materially greater than it, is at theentrance end.

As shown, the cylindrical filler is disposed between two reticulated orrelatively rigid concavoconvex screen partitions l1 disposed, at therespective, ends of the, tube. The reticulated members may be shellmembers provided with a multiplicity of very closely spaced smallperforations or may be in the form of rigid metal netting of small mesh.

It will be understoodthat while I prefer densely compressed, steel woolfor the filler of my tube,

that other metal fibers matted together and densely compressed or otherforms of metal particles, such as compressed metal granules preferablyiron or steel having a dense porosity, may be utilized. It is essentialthat the character of the metal. be such that it will have a relativelyhigh melting point above the temperatures utilized in vaporizing theleaded fuel.

, I prefer'to construct the filler of my generating tube from aplurality of abutting plugs of compressed metallic fibers or particles.As shown eight, of said plugs disposed end to end in tube H are utilizedbut, of course the number thereof and lengths of the same may beconsiderably varied. It is important, however, that the density of' theright hand plug as be less than the extreme left hand plug iii and Iprefer to utilize a number of plugs E8 of similar compression anddensity and then utilize one or more intermediate plugs 20 of greaterdensit than the plugs 18 but of less density than the plug isimmediately adjacent the discharge of the tube.

In utilizing the preferred fibrous metal of relatively high meltingpoint, such as steel wool, a proper density of the various plug membersit, land 28 may be readily and accurately obtained by successivelinserting uncompressed bats of the proper diameter to fit the fuelentrance end of tube H with disc 12 removed and the disc I3 applied andcompressing the first bat of steel wool or fibrous metal. to the desireddetermined position by a piston inserted through the open end of thetube and then applying a second bat of steel wool or fibrous metal andcompressing this bat upon the compressed plug i9 by the same pistonaction, the inward movement of the piston indicating throughpredetermined means the compression and density desired and thereaftersuccessively introducing uncompressed bats of fibrous metal andcompressing by piston action to the extent gauged to obtain the plugsi8, thereafter the grating or reticulated discs I! with its supportingclip may be inserted and the tube closed at the fuel entrance end bywelding or otherwise, securing the disc I2 in the rabbeted end of thetube.

Referring now to Fig. 2, there is there shown a, supply pipe 3|, whichwill supply the fuel, such as gasoline containing tetra-ethyl lead, froma source of' supply such as a fuel tank under air The filler is verypreferably com-- pressure to. the plug M, a coupling 32 being employedfor connecting the delivery end of the fuel supply pipe to the plug Id.The branch discharge nipple is has quite a small passage therethrougl1and; it leads into a U-shaped mixing. chamber 33, this chamber having anair opening 33a beyond'the point where nipple Hia delivers into thesame. The mixing chamber 33 connects with; a manifold 34, which hasconnected thereto a burner 35 underlying the generator tube H andadapted to deliver heat thereto when in operation.

In carrying out my method and in the operation of the apparatusillustrated, when the apparatus is infull operation, leaded hydrocarbonfuel, such as gasoline containing tetra-ethylleadis.introduced underpressure through the fuel supply pipe 3| and nipple l4 into thegenerator tube H.

The generator tube is heated by the burner 35'.

and. the gasoline is generated into gas in the generator tube, thegenerator tube delivering throughthe nipple ifia, into the mixingchamber 33 where the gas mixes with air admitted'through the opening 33aand the mixed air and gas then pass through the manifold 34 to, deliverfrom the burner 35 where it is burned. The heat delivered from theburner 35 intensely heats the generator tube I! together with the steelwool. plugs I8, i9, and Zll to maintain the metal particles or fibers athigh temperatures.

The tube is of such diameter and length that actual passage of the fueltherethrough is slow, the globules of the tetra-ethyl lead passingthrough the less compressed and less dense pads i8 until cracking ordecomposition of the tetraethyl lead takes place in the vaporizing orthe gasoline. As decomposition or cracking of the tetra-ethyl leadcommences, liberation of atoms or fine particles of the element lead, isthought to be produced within the tube with some small formation of leadoxide in minute particles be- :cause of the small amounts of air admixedwith the leaded gasoline. These particles impinge against and some arerestricted by the fine :porosity of the plugs H but it is believed thatthelead atoms or minute particles in molten state, unite with theparticles of iron at high temperature usually incandescent to formminute quantitiesof lead-iron alloy. Certain metals have an affinity orability to form alloys and; this is true of metals, lead" and iron. Inany event, in the vaporization of the fuel and in the materialdecomposition of the tetra-ethyl lead as the mixture passes through thevery finely porous plugs [8, the lead constituents of the tetra-ethyllead are removed and this I am convinced is through. action in additionto mechanical filtering. In the more volatile state and with greaterdecomposition of the tetra-ethyl lead near the discharge end of tube H,the plugs 28- and I9 are successively denser thereby producing greaterimpingement ofthe remaining molten particles offree- .lead and servingits substantially eliminate all.

with the proper use of my method and apparatus.

Examination of filler plugs l8, l9 and 20 have been made by opening up anumber of my generator tubes after many hours of actual operation of theburner system and have revealed what apears to be alloy coatings uponthe particles or fibers of the steel wool.

It will, of course, be understood that the filler bats have to beoccasionally renewed, or what is usually simpler, a new generator tubewith my improvements therein, installed for replacement. In theapparatus herein described, with the tube and bats of suitable sizefor'the requirements, several hundred hours of operating use may beobtained where leaded gasoline is burned before replacement is needed.This means that in most commercial devices the system may be operativefrom six months to over a year without replacement of the filler plugsor generator tube.

I realize that in the high temperature heating action of the leadedgasoline within the generator tube and in the heating of the metallicfibers or particles preferably of steel composition many complicatedphysical and chemical reactions occur. I cannot positively state whatcauses the unexpected elimination of substantially all of the leadingredients during vaporization or immediately thereafter, but I believethere are several factors which may include reactions occurring throughcarbon in the steel particles; formation of small amounts of alloy withthe lead and heated steel, or iron; some other attraction or affinitybetween the extremely minute lead atoms or particles and certainlydecomposition or cracking in the generating tube of the tetraethyl leadglobules. In any event, I am positive of the successful results producedby carrying out my method as disclosed herein and by the use of thesimple apparatus described.

Where in the appended claims the term "particles is used, it is used inits broad sense to indicate elements of very small cross sectional areawhether in the shape of filaments, fibers or minute granules.

Where in the appended claims the term separated 01f is used, it is usedin its broad sense to include within its meaning any action whetherthrough attraction, surface tension, alloy ailinity, or pure physicalfiltering to retain the lead ingredient.

In Figure 5 a satisfactory form of apparatus is illustrated wherein themedium for separating off the residue particles from decomposedtetraethyl lead is isolated from the generator tube but closelyassociated therewith. In this form of my invention the generator tube 25is of conventional structure and may or may not have a filling thereinto prevent pulsations or choking and has its discharge end connected bya short tube 28 with the intake 21 of a residue removing retort or tube28. Tube 28 is preferably of considerably greater diameter than thevaporizing tube 25 and in general is constructed similarly to the tube Hof the form first described, having a discharge tube 29 at one endthereof and being substantially filled throughout its cross sectionalarea with preferably densely compressed plugs or a plug of metallicfibrous material preferably steel wool or some other fibrous ironcontaining metal. In the tube 28 the heavy screens 30 are of similarconstruction to the retaining screens l1 shown in the form firstdescribed, but are related somewhat different as shown both having theconcave portions disposed inwardly relatively to the respective ends ofthe tube. The filler F of steel wool or the like is as in the form ofthe invention first described preferably constructed and compressed insuch manner that the plug or portion of the filler at the discharge endof the tube is of greater compressed density than the portion of thefiller at the intake end.

In operation the vaporized fuel with free particles of lead andparticles of lead oxide mixed therewith at high temperature pass intothe intake end of tube 28 and then are affected by the filler F in thesame manner as in the preferred form previously described. The volatilematerial passes through the filler F whereas the lead atoms orparticlesand other residue particles impinge against the many matted fibers orparticles of steel wool and react therewith and are separated off asdescribed with reference to the form first described. It is, of course,essential that the temperature within the filler F be adequate to retainthe fuel in vaporized state, and for thispurpose there is shown a burner36 underlying both tubes 25 and 28 and playing thereon.

What I claim is:

1. Apparatus for substantially removing the lead containing ingredientsof hydrocarbon fuels containing tetra-ethyl lead, comprising a retortadapted to be subjected to high temperatures, said retort having a fuelentrance and a fuel discharge, a filler occupying at least a portion ofthe interior of said retort between said entrance and said discharge,said filler being composed of a mass of densely related iron containingparticles, said particles adjacent the discharge portion of said retortbeing more densely related than said particles adjacent the fuel intakeportion of said retort.

2. The method of generating hydrocarbon fuels containing tetra-ethyllead to successfully burn the same in burners of the pressure type,which consists in heating the fuel to vaporize the hydrocarbons anddecompose the tetra-ethyl lead and passing the fuel in such conditionthrough a mass of successively more densely compressed and matted metalfibers, which, while permitting passage of the vaporized hydrocarbonelements for burning, will act to catch, retain, and substantiallyremove from the vaporized hydrocarbons the decomposed elements of thetetra-ethyl lead.

SOPHUS RASMUSSEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 646,558 Rey et a1. Apr. 3, 1900666,785 Williams Jan. 29, 1901 944,456 Miess Dec. 28, 1909 1,594,296 LeeNov. 9, 1921 1,604,235 Odom Oct. 26, 1926 1,676,724 Pecker July 10, 19281,962,153 Peterkin June 12, 1934 2,368,261 Neef Jan. 30, 1945 2,397,142Howard Mar. 26, 1946 FOREIGN PATENTS Number Country Date 312,200 GreatBritain May 21, 1929 728,741 France Apr. 18, 1932 OTHER REFERENCES Tomset al., The Separation of Lead Tetra- Ethyl-Petro1eum Spirit, Analyst 53(1928), pages 328 to 329.

